Positioning stabilizer assembly using shoulder ring

ABSTRACT

A stabilizer assembly using a shoulder ring. The drilling tool may include a housing having one or more external splines disposed along an outer surface of the housing. The drilling tool may also include a rotatable shaft disposed inside the housing, the shaft having a downhole end portion configured to be coupled to a drill bit. The drilling tool may further include a stabilizer assembly movably coupled to the housing. In addition, the drilling tool may include a shoulder ring having one or more internal splines disposed on an inner surface thereof, the shoulder ring disposed around the housing and configured to prevent uphole movement of the stabilizer assembly when the one or more internal splines of the shoulder ring are engaged with the one or more external splines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of related U.S. Provisional Application Ser. No. 61/740,421 filed Dec. 20, 2012, titled “Positioning Stabilizer Assembly Using Shoulder Ring,” to Vanecko et al., the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND

The following descriptions and examples do not constitute an admission as prior art by virtue of their inclusion within this section.

Drilling tools, such as drilling motors, may be used to provide rotational force to a drill bit when drilling earth formations. Drilling motors used for this purpose may be driven by drilling fluids pumped from surface equipment through a drill string. This type of drilling motor may be referred to as a mud motor. In use, the drilling fluid may be forced through the mud motor, which may extract energy from the flow to provide rotational force to a drill bit located below the mud motor. A mud motor may include a positive displacement motor (PDM) or a turbodrill.

For some mud motors, a stabilizer may be used to guide a housing, a shaft, and a drill bit of the mud motor in a wellbore. In particular, the stabilizer may be disposed on the housing to reduce spiraling of the mud motor, helping to keep the mud motor centered within the wellbore. In some examples, the stabilizer may be positioned proximate to a lower end portion of the housing, where the drill bit may be coupled to the shaft extending from the lower end portion of the housing.

The stabilizer may be positioned such that a portion of the shaft, including a gripping area, which extends from the lower end portion of the housing may be accessed without interference from the stabilizer. The gripping area may be used by a gripping tool to hold the shaft while make-up torque or breakout torque is applied on the drill bit.

During operation of the mud motor, certain drilling fluids may erode an exposed portion of the shaft, including the gripping area. If the gripping area were to erode, then the gripping tool may be unable to properly grip the shaft to allow the application of the make-up torque and/or breakout torque on the drill bit. To overcome the issue of erosion, the stabilizer may be positioned closer to the drill bit to protect/cover the gripping area from the erosive qualities of the drilling fluid. Alternatively, a longer stabilizer may be used to cover the gripping area. In some cases, the longer stabilizer may require a specialized gripping tool to apply make-up torque or breakout torque on the drill bit. Consequently, an inventory of different housing bodies, stabilizers having varying lengths, and specialized gripping tools may be needed, leading to increased maintenance and/or operating costs for a mud motor over time.

SUMMARY

Described herein are implementations of various technologies for positioning a stabilizer assembly using a shoulder ring. In one implementation, a drilling tool may include a housing having one or more external splines disposed along an outer surface of the housing. The drilling tool may also include a rotatable shaft disposed inside the housing, the shaft having a downhole end portion configured to be coupled to a drill bit. The drilling tool may further include a stabilizer assembly movably coupled to the housing. In addition, the drilling tool may include a shoulder ring having one or more internal splines disposed on an inner surface thereof, the shoulder ring disposed around the housing and configured to prevent uphole movement of the stabilizer assembly when the one or more internal splines of the shoulder ring are engaged with the one or more external splines.

In another implementation, a drilling tool may include a housing having one or more external splines disposed along an outer surface of the housing. The drilling tool may also include a rotatable shaft disposed inside the housing, the shaft having a downhole end portion configured to be coupled to a drill bit. The drilling tool may further include a stabilizer assembly movably coupled to the housing. In addition, the drilling tool may include one or more spacers disposed around the housing between the shoulder ring and the stabilizer assembly. Further, the drilling tool may include a shoulder ring disposed around the housing and configured (i) to prevent uphole movement of the stabilizer assembly when one or more internal splines of the shoulder ring are engaged with the one or more external splines and (ii) to allow uphole movement of the stabilizer assembly when the one or more internal splines are disengaged from the one or more external splines.

In yet another implementation, an apparatus for use with a drilling tool may include a shoulder ring having one or more internal splines configured to be engaged with one or more external splines disposed around a housing of a drilling tool. The apparatus may also include a blocking ring configured to be engaged with the shoulder ring, where the blocking ring includes a downhole ring configured to abut a downhole end portion of the shoulder ring. Further, each of the downhole ring and the shoulder ring may have an inner diameter greater than an outer diameter of the one or more external splines. The blocking ring may also include one or more spline arms extending in an axial direction from the downhole ring, where an inner diameter of the spline arms is less than an inner diameter of the downhole ring.

The above referenced summary section is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description section. The summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of various techniques will hereafter be described with reference to the accompanying drawings. It should be understood, however, that the accompanying drawings illustrate only the various implementations described herein and are not meant to limit the scope of various techniques described herein.

FIG. 1 illustrates a view of a turbodrill in accordance with implementations of various techniques described herein.

FIG. 2 illustrates an exploded view of a downhole portion of a turbodrill in accordance with implementations of various techniques described herein.

FIG. 3 illustrates a view of the housing of a downhole portion of a turbodrill in accordance with implementations of various techniques described herein.

FIG. 4 illustrates a perspective view of a shoulder ring in accordance with implementations of various techniques described herein.

FIGS. 5-9 illustrate perspective views of the downhole portion of a turbodrill in accordance with implementations of various techniques described herein.

FIG. 10 illustrates an exploded view of a downhole portion of a turbodrill in accordance with implementations of various techniques described herein.

FIG. 11 illustrates a view of a housing of a downhole portion of a turbodrill in accordance with implementations of various techniques described herein.

FIGS. 12 and 13 illustrate views of a blocking ring in accordance with implementations of various techniques described herein.

FIGS. 14 and 15 illustrate a shoulder ring engaged with a blocking ring in accordance with implementations of various techniques described herein.

FIG. 16 illustrates a view of the downhole portion of a turbodrill in accordance with implementations of various techniques described herein.

FIGS. 17 and 18 illustrate a shoulder ring engaged with a blocking ring in accordance with implementations of various techniques described herein.

FIG. 19 illustrates a view of the downhole portion of a turbodrill in accordance with implementations of various techniques described herein

DETAILED DESCRIPTION

The discussion below is directed to certain specific implementations. It is to be understood that the discussion below is only for the purpose of enabling a person with ordinary skill in the art to make and use any subject matter defined now or later by the patent “claims” found in any issued patent herein.

It is specifically intended that the claimed invention not be limited to the implementations and illustrations contained herein, but include modified forms of those implementations including portions of the implementations and combinations of elements of different implementations as come within the scope of the following claims. Nothing in this application is considered critical or essential to the claimed invention unless explicitly indicated as being “critical” or “essential.”

Reference will now be made in detail to various implementations, examples of which are illustrated in the accompanying drawings and figures. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits and networks have not been described in detail so as not to unnecessarily obscure aspects of the various implementations described herein.

It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first object or step could be termed a second object or step, and, similarly, a second object or step could be termed a first object or step, without departing from the scope of the invention. The first object or step, and the second object or step, are both, objects or steps, respectively, but they are not to be considered the same object or step.

The terminology used in the description of the present disclosure herein is for the purpose of describing particular implementations only and is not intended to be limiting of the present disclosure. As used in the description of the present disclosure and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.

As used herein, the term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

As used herein, the terms “up” and “down;” “upper” and “lower;” “upwardly” and downwardly;” “below” and “above;” and other similar terms indicating relative positions above or below a given point or element may be used in connection with some implementations of various technologies described herein. However, when applied to equipment and methods for use in wells that are deviated or horizontal, or when applied to equipment and methods that when arranged in a well are in a deviated or horizontal orientation, such terms may refer to a left to right, right to left, or other relationships as appropriate.

The following paragraphs provide a brief summary of various technologies and techniques directed at positioning a stabilizer assembly using a shoulder ring described herein.

In one implementation, a turbodrill may include a housing, a shoulder ring, one or more spacers, and a stabilizer assembly. The turbodrill may be configured such that the shoulder ring, the spacers and the stabilizer assembly are disposed around the downhole portion of the housing. The housing may include one or more external splines disposed along an outer diameter of the housing. Each external spline may include at least one lip extending in a downhole direction from a base. Further, a rotatable shaft may extend from the housing, where a drill bit may be coupled to a downhole end portion of the shaft.

The shoulder ring may include one or more internal splines disposed along an inner diameter of the shoulder ring, where the internal splines may be configured to engage the external splines. In one implementation, the inner diameter of the shoulder ring may be greater than the outer diameter of the external splines.

The turbodrill may use the stabilizer assembly in conjunction with the shoulder ring to cover a portion of the shaft. In operation, the internal splines of the shoulder ring may engage the external splines of the housing such that the shoulder ring may be prevented from traveling uphole along the housing. As such, the shoulder ring may be placed in a “locked” position. When the shoulder ring is placed in the locked position, the spacers and the stabilizer assembly may be prevented from traveling to a position uphole relative to the external splines. In this configuration, the stabilizer assembly is made-up.

Once made up, the stabilizer assembly may cover a portion the shaft extending from the housing, including a gripping area of the shaft, thereby protecting the gripping area from the erosive qualities of the drilling fluid. In one implementation, the one or more spacers may be used to adjust the extent to which the stabilizer assembly covers the shaft.

As disclosed above, a portion of the shaft extending from the housing, e.g., the gripping area, may need to be accessed without interference from the stabilizer assembly. As such, in one implementation, in order to access the shaft where the stabilizer assembly is made-up and in the covered position, the stabilizer assembly may be moved uphole from its covered position.

In moving the stabilizer assembly uphole, the stabilizer assembly may first be moved downhole at a sufficient distance to allow the internal splines of the shoulder ring to be positioned downhole relative to the at least one lip of the external splines. The shoulder ring may then be shifted circumferentially about the housing such that each internal spline may be aligned with a gap. In this manner, the shoulder ring may be placed in an “unlocked” position. The shoulder ring may then be moved in an uphole direction by passing over the external splines. The stabilizer assembly may then be moved uphole until the stabilizer assembly reaches a position such that the gripping area may be accessible by the gripping tool.

In one implementation, a turbodrill may use a stabilizer assembly and a shoulder ring in conjunction with a blocking ring, where the blocking ring may be used to help cover sharp edges of the external splines and to limit the flow of drilling fluid through the gaps between the external splines. The blocking ring is configured to engage with the shoulder ring. In one implementation, the blocking ring may be used to fill the gaps between the external splines.

The blocking ring may include a downhole ring and one or more spline arms. Further, each spline arm may include an axial arm and a block arm. Further, an outer diameter of the spline arms may be substantially equal to the outer diameter of the external splines, thereby allowing the spline arms to form a relatively smooth transition with the external splines when filling the gaps. Each axial arm may extend axially from the downhole ring. Each block arm may extend laterally from the axial arm, where each block arm may be configured to cover a gap along the housing. Accordingly, each block arm may be less than, but substantially equal to, each gap with respect to circumferential length.

Various implementations described above will now be described in more detail with reference to FIGS. 1-19.

Turbodrill with Stabilizer

The following implementations focus primarily on turbodrills. However, those skilled in the art will appreciate that positioning a stabilizer assembly using a shoulder ring as disclosed herein may be similarly performed in other drilling tools, such as a positive displacement motor (PDM).

FIG. 1 illustrates a view of a turbodrill 100 in connection with implementations of various techniques described herein. A housing 110 includes an uphole connection 115 to couple to a drill string. Turbine stages 120 are disposed within the housing 110 and may be used to rotate a shaft 130. At a downhole end portion of the turbodrill 100, a drill bit 125 may be attached to the shaft 130 by a downhole connection (not shown).

The turbodrill 100 may use turbine stages 120 to provide rotational force to the drill bit 125. The turbine stages 120 may consist of one or more non-moving stator blades and a rotor assembly having rotating blades mechanically linked to the shaft 130. The turbine stages 120 may be designed such that the blades of the stator stages direct a flow of drilling fluid into corresponding rotor blades to provide rotation to the shaft 130, where the shaft 130 ultimately couples to and drives the drill bit 125. Thus, the high-speed drilling fluid flowing into the rotor blades may cause the rotor and the drill bit to rotate with respect to the housing 110. The turbodrill 100 may include radial bearings 170 provided between the shaft 130 and the housing 110, where the radial bearings 170 may help keep the shaft 130 concentric within the housing 110.

While providing rotational force to the shaft 130, the turbine stages 120 may also produce a downhole axial force, or thrust, from the drilling fluid. The downhole thrust, however, may produce a higher weight on bit (WOB) than required for operation of the turbodrill 100. To mitigate the effects of excess thrust in the turbodrill 100, thrust bearings 140 may be provided. The thrust bearings 140 may include steel roller bearings, polycrystalline diamond compact (“PDC”) surface bearings, or any other implementation known to those skilled in the art.

In addition, stabilizers 160 and 161 may be disposed on the housing 110 to help keep the turbodrill 100 centered within a wellbore. The stabilizers 160 and 161 may be used to guide the housing 110, the shaft 130, and the drill bit 125 in the wellbore. In particular, the stabilizers 160 and 161 may be disposed on the housing 110 to reduce spiraling of the turbodrill 100, helping to keep the turbodrill 100 centered within the wellbore. In one implementation, the stabilizer 161 may be positioned proximate to a downhole end portion of the housing 110, where the shaft 130 may extend from the downhole end portion of the housing 110.

Stabilizer Assembly Using Shoulder Ring

FIG. 2 illustrates an exploded view of a downhole portion of a turbodrill 200 in accordance with implementations of various techniques described herein. The turbodrill 200 may include a housing 210, a shoulder ring 220, one or more spacers 230, and a stabilizer assembly 240. The turbodrill 200 may be configured such that the shoulder ring 220, the spacers 230 and the stabilizer assembly 240 are disposed around the downhole portion of the housing 210. The stabilizer assembly may be movably coupled to the housing via threads 214. The shoulder ring 220 may be positioned uphole relative to the spacers 230, and the spacer 230 may be positioned uphole relative to the stabilizer assembly 240. In one implementation, the turbodrill 200 may not have any spacers 230.

FIG. 3 illustrates a view of the housing 210 of the downhole portion of the turbodrill 200 in accordance with implementations of various techniques described herein. The housing 210 may include one or more external splines 216 disposed along an outer diameter of the housing 210. The outer diameter of the housing 210 may be less than an outer diameter of the external splines 216. Each external spline 216 may include at least one lip 217 extending in a downhole direction 201 from a base 218. In one implementation, each external spline 216 may include two lips 217 extending from the base 218.

In another implementation, the external splines 216 may be distributed equidistantly along the outer diameter of the housing 210. In a further implementation, the number of external splines is minimized so as to maximize a surface area of the housing 210 to which stress is applied. The housing 210 may also include one or more gaps 219 formed between the one or more external splines 216.

The housing 210 may include threads 214 for engaging the stabilizer assembly 240 (FIG. 2), where the threads are located downhole from the external splines 216. A rotatable shaft (not pictured) may extend from the housing 210, where a drill bit (not pictured) may be coupled to a downhole end portion of the rotatable shaft.

FIG. 4 illustrates a perspective view of the shoulder ring 220 in accordance with implementations of various techniques described herein. The shoulder ring 220 may include one or more internal splines 222 disposed along an inner diameter of the shoulder ring 220, where the internal splines 222 may be configured to engage the external splines 216 (FIG. 3). In one implementation, the internal splines 222 may taper towards a downhole side of the shoulder ring 220.

In another implementation, the internal splines 222 may be distributed equidistantly along the inner diameter of the shoulder ring 220. In yet another implementation, the inner diameter of the shoulder ring 220 may be greater than the outer diameter of the external splines 216. The shoulder ring 220 may be constructed using steel, titanium, or any other implementation known to those skilled in the art.

Covering the Shaft

In one implementation, a turbodrill may use the stabilizer assembly 240 in conjunction with the shoulder ring 220 to cover a portion of a shaft. In such an implementation, in operation, the internal splines 222 of the shoulder ring 220 may engage the external splines 216 of the housing 210 such that the shoulder ring 220 may be prevented from traveling uphole along the housing 210 (i.e., internal splines 222 engage bases 218 of external splines 216). In this implementation, the shoulder ring 220 may be placed in a “locked” position.

FIG. 5 illustrates a perspective view of the downhole portion of the turbodrill 200 in accordance with implementations of various techniques described herein, where the shoulder ring 220 is placed in the locked position. With the shoulder ring 220 in the locked position, the spacers 230 and the stabilizer assembly 240 may be prevented from traveling to a position uphole relative to the external splines 216. That is, the stabilizer assembly 240 may be made-up to the spacers 230 such that the stabilizer assembly 240 and the spacers 230 are prevented from traveling further uphole along the housing 210. The stabilizer assembly 240 may be made-up by traveling along the housing 210 via the threads 214. In one implementation, if no spacers 230 are used, then the stabilizer assembly 240 may be made-up directly to the shoulder ring 220.

FIG. 6 illustrates a perspective view of the downhole portion of the turbodrill 200 in accordance with implementations of various techniques described herein, where the stabilizer assembly 240 may be made-up. As shown in FIG. 6, the stabilizer assembly 240 may be made-up to the spacer 230 such that the stabilizer assembly 240 is prevented from traveling further uphole along the housing 210 by the spacer 230. The at least one lip 217 (FIG. 3) may be configured to handle a frictional load from the one or more spacers 230 or the stabilizer assembly 240 as it is being made up.

As disclosed above, the made-up stabilizer assembly 240 may protect a portion of the shaft extending from the housing 210, such as the gripping area, from erosive qualities of drilling fluid used in the turbodrill 200. In particular, the made-up stabilizer assembly 240 may cover the gripping area.

In one implementation, the one or more spacers 230 may be used to adjust the extent to which the stabilizer assembly 240 covers the shaft. For example, spacers 230 of shorter axial length may be used such that the stabilizer assembly 240 covers less of the shaft. In contrast, spacers 230 of longer axial length may be used such that the stabilizer assembly 240 covers more of the shaft. In another implementation, an axial length of the shoulder ring 220 may similarly be altered to adjust the extent to which the stabilizer assembly 240 covers the shaft. In yet another implementation, the number of spacers 230 may be increased or decreased to modify the extent to which the stabilizer assembly 240 covers the shaft.

Accessing the Shaft

As disclosed above, a portion of the shaft extending from the housing 210, such as the gripping area, may need to be accessed without interference from the stabilizer assembly 240. For example, the gripping area may need to be accessed to secure the shaft via a gripping tool as make-up torque and/or breakout torque is applied on the drill bit (FIG. 1).

In one implementation, the stabilizer assembly 240 may be used with spacers 230 of shorter axial length (or no spacer 230) so that a portion of the shaft may be easily accessible.

In order to access the portion of the shaft covered by the made-up stabilizer assembly 240, the stabilizer assembly 240 may be moved uphole. To move the stabilizer assembly 240 uphole from its covered position, the stabilizer assembly 240 may initially be moved downhole (i.e., by unthreading the stabilizer assembly 240 from the housing 210 via threads 214) to allow the spacers 230 and the shoulder ring 220 to also move downhole. The stabilizer assembly 240 may be moved downhole by a distance until the internal splines 222 of the shoulder ring 220 are positioned downhole relative to the at least one lip 217 of the external splines 216. In one implementation, the length of the at least one lip 217 may be as short as allowed under design constraints, thereby minimizing the distance needed for the shoulder ring 220, stabilizer assembly 240 and any spacers 230 to move downhole.

The shoulder ring 220 may then be rotated circumferentially about the housing 210 such that each internal spline 222 may be aligned with a gap 219. As such, the shoulder ring 220 may be placed in an “unlocked” position. The shoulder ring 220 may then be moved in an uphole direction by passing over the external splines 216, while the internal splines 222 are passing through the gaps 219. FIG. 7 illustrates a perspective view of the downhole portion of the turbodrill 200, where the shoulder ring 220 may be positioned uphole relative to the external splines 216.

The one or more spacers 230 may then be moved such that the spacers 230 may be positioned uphole relative to the external splines 216. FIG. 8 illustrates a perspective view of the downhole portion of the turbodrill 200, where the spacers 230 are positioned uphole relative to the external splines 216. The inner diameter of the spacers 230 may be greater than the outer diameter of the external splines 216 such that the spacers 230 pass over the threads 214 of housing 210 and over the external splines 216 disposed on the surface of housing 210.

The stabilizer assembly 240 may then be moved uphole until the stabilizer assembly 240 reaches an “uncovered” position, in which a portion of the shaft extending from the housing 210 may be accessed. In particular, the stabilizer assembly 240 in the uncovered position may allow access to the gripping area of the shaft. FIG. 9 illustrates a perspective view of the downhole portion of the turbodrill 200, where the stabilizer assembly 240 has been moved uphole to allow access to a portion of the shaft (not pictured) extending from the housing 210. The stabilizer assembly 240 may be moved in the uphole direction via the threads 214.

Stabilizer Assembly Using Shoulder Ring and Blocking Ring

In one implementation, a turbodrill may use a stabilizer assembly and a shoulder ring in conjunction with a blocking ring, where the blocking ring may be used to help cover sharp edges of the external splines and to limit the flow of drilling fluid through the gaps between the external splines.

FIG. 10 illustrates an exploded view of a downhole portion of a turbodrill 1000 in accordance with implementations of various techniques described herein. In one implementation, the turbodrill 1000 may include a housing 1010, one or more external splines 1016, one or more gaps 1019, a gripping area 1011, a shaft 1012, threads 1014, a shoulder ring 1020 with one or more internal splines 1022, a blocking ring 1050, one or more spacers 1030, a stabilizer assembly 1040, and a drill bit 1060. These components may be similar to those discussed with respect to FIGS. 2-9. FIG. 11 illustrates a close up view of the external splines 1016. As shown, each external spline 1016 has only one lip 1017 extending from a base 1018. In addition, the blocking ring 1050 may be configured to engage with the shoulder ring 1020, as discussed below with respect to FIGS. 12 and 13.

FIGS. 12 and 13 illustrate perspective views of the blocking ring 1050 in accordance with implementations of various techniques described herein. In one implementation, the blocking ring 1050 may be used to fill the one or more gaps 1019 between the external splines 1016 (FIG. 11). The blocking ring 1050 may be constructed using steel, titanium, or any other implementation known to those skilled in the art.

The blocking ring 1050 may include a downhole ring 1052 and one or more spline arms 1054. Each spline arm 1054 may include an axial arm 1055 and a block arm 1056. In one implementation, the downhole ring 1052 may have an inner diameter greater than an outer diameter of the external splines 1016. Further, an outer diameter of the downhole ring 1052 may be substantially similar to an outer diameter of the shoulder ring 1020.

In another implementation, the one or more spline arms 1054 may extend in an uphole direction from the downhole ring 1052. An inner diameter of the spline arms 1054 may be less than the inner diameter of the downhole ring 1052. Further, an outer diameter of the spline arms 1054 may be substantially equal to the outer diameter of the external splines 1016, thereby allowing the spline arms 1054 to form a relatively smooth transition with the external splines 1016 when filling the gaps 1019. In one implementation, the number of spline arms 1054 deployed in the blocking ring 1050 may be equal to the number of gaps 1019.

In one implementation, each axial arm 1055 of the spline arms 1054 may extend axially from the downhole ring 1052, where an axial length of the axial arm 1055 may be equal to at least an axial length of the internal splines 1022 (FIG. 10). Further, each axial arm 1055 may be circumferentially spaced from one another to allow an internal spline 1022 to transition between a locked position and an unlocked position, as discussed below with respect to FIGS. 17-19. In addition, each axial arm 1055 may be configured to be disposed under the shoulder ring 1020.

Each block arm 1056 may be configured to extend laterally from its respective axial arm 1055, such that the block arm 1056 and the axial arm 1055 substantially form an L-shape. In addition, each block arm 1056 may be configured to cover (circumferentially and/or radially) a gap 1019 along the housing 1010. Accordingly, each block arm 1056 may be less than, but substantially equal to, each gap 1019 with respect to circumferential length. Further, an uphole end portion of each block arm 1056 may be aligned with an uphole end portion of each external spline 1016, such that the block arms 1056 and the external splines 1016 are configured to form a relatively smooth transition along the housing 1010, as discussed below with reference to FIG. 16. As such, the geometric dimensions of each block arm 1056 may be substantially similar to those of each base 1018.

Covering the Shaft

FIGS. 14 and 15 illustrate the shoulder ring 1020 engaged with the blocking ring 1050 in accordance with implementations of various techniques described herein. Further, while not easily perceived from the view of FIG. 14, FIG. 15 illustrates an outline of the placement of the internal splines 1022. In one implementation, while engaged, a downhole end portion of the shoulder ring 1020 may abut an uphole end portion of the downhole ring 1052.

Further, as illustrated, the shoulder ring 1020 may be in its locked position, where the internal splines 1022 of the shoulder ring 1020 may engage the external splines 1016 of the housing 1010 such that the shoulder ring 1020 may be prevented from traveling uphole along the housing 1010. While in the locked position, the block arms 1056 may be positioned adjacent to the internal splines 1022 when filling the gaps 1019. The block arms 1056 and the external splines 1016 may be configured to form a relatively smooth transition along the housing 1010.

Similar to the turbodrill 200 discussed with respect to FIGS. 5 and 6, when the shoulder ring 1020 is placed in the locked position, the spacers 1030 and the stabilizer assembly 1040 may be prevented from traveling to a position uphole relative to the external splines 1016. Further, the blocking ring 1050 may be prevented from traveling uphole relative to the external splines 1016 (i.e., due to abutment between blocking ring 1050 and locked shoulder ring 1020).

Similar to the turbodrill 200 shown in FIG. 6, FIG. 16 illustrates a perspective view of the downhole portion of the turbodrill 1000 in accordance with implementations of various techniques described herein, where the shoulder ring 1020 may be placed in the locked position and the stabilizer assembly 1040 may be made-up. Further, FIG. 16 also illustrates an outline of the placement of the internal splines 1022. In one implementation, the spacers 1030 may abut a downhole end portion of the downhole ring 1052 when the stabilizer assembly 1040 is made-up.

Once made up, similar to the turbodrill 200 of FIG. 6, the stabilizer assembly 1040 may cover at least a portion the shaft 1012 extending from the housing 1010, including the gripping area 1011 (not pictured) of the shaft 1012.

Accessing the Shaft

FIGS. 17 and 18 illustrate the shoulder ring 1020 engaged with the blocking ring 1050 in accordance with implementations of various techniques described herein. FIG. 17 may be similar to FIG. 14, and FIG. 18 may be similar to FIG. 15. However, in FIGS. 17 and 18, the shoulder ring 1020 may be placed in an “unlocked” position, where the shoulder ring 1020 may be shifted circumferentially about the housing 1010 (FIG. 10) such that each internal spline 1022 may be aligned with the gap 1019. While in the unlocked position, an uphole end portion of the internal splines 1022 may abut the block arms 1056. Such abutment results from the shoulder ring 1020 being rotated circumferentially such that both the internal splines 1022 and the block arms 1056 align with gaps 1019. The block arms 1056 and the external splines 1016 may still be configured to form a relatively smooth transition along the housing 1010.

Similar to the turbodrill 200 described with respect to FIG. 7, and prior to shifting the shoulder ring 1020 to the unlocked position, the stabilizer assembly 1040 and the blocking ring 1050 may be moved downhole in conjunction at a sufficient distance to allow the internal splines 1022 to be placed downhole relative to the external splines 1016. After shifting to the unlocked position, the shoulder ring 1020 and the blocking ring 1050 may then be moved in an uphole direction by passing over the external splines 1016, whereby the internal splines 1022 may pass through the gaps 1019. In particular, the downhole ring 1052 may pass over the external splines 1016 (FIG. 10), while the spline arms 1054 may pass through the gaps 1019. The shoulder ring 1020 and the blocking ring 1050 may then be disengaged from the other when both are uphole relative to the external splines 1016.

Similar to FIG. 7, FIG. 18 illustrates a perspective view of the downhole portion of the turbodrill 1000 in accordance with implementations of various techniques described herein, where the shoulder ring 1020 and the blocking ring 1050 may be positioned uphole relative to the external splines 1016. The stabilizer assembly 1040 and/or the spacers 1030 may then be moved uphole until the stabilizer assembly 1040 reaches the “uncovered” position, in which a portion of the shaft 1012, e.g., the gripping area 1011 (FIG. 10), may be accessed. Similar to FIG. 9, FIG. 19 illustrates a perspective view of the downhole portion of the turbodrill 1000, where the stabilizer assembly 1040 has been moved uphole to allow access to the gripping area 1011.

In sum, various implementations described above with respect to FIGS. 1-19 may allow for the placement of stabilizer assemblies at various positions along a turbodrill housing through the use of shoulder rings and/or spacers. In addition, various implementations described herein may be used to protect portions of a shaft, such as a gripping area, from erosive material while also having an opportunity to access said portions of the shaft for gripping purposes. Further, positioning the same stabilizer assembly along the housing may reduce the need for an inventory of varying housing bodies, stabilizers and/or specialized gripping tools. Instead, a shoulder ring and/or a cheaper inventory of varying spacers may be used.

While the foregoing is directed to implementations of various techniques described herein, other and further implementations may be devised without departing from the basic scope thereof. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. 

What is claimed is:
 1. A drilling tool, comprising: a housing having one or more external splines disposed along an outer surface of the housing; a rotatable shaft disposed inside the housing, the shaft having a downhole end portion configured to be coupled to a drill bit; a stabilizer assembly movably coupled to the housing; and a shoulder ring having one or more internal splines disposed on an inner surface thereof, the shoulder ring disposed around the housing and configured to prevent uphole movement of the stabilizer assembly when the one or more internal splines of the shoulder ring are engaged with the one or more external splines.
 2. The drilling tool of claim 1, wherein the shoulder ring is configured to allow uphole movement of the stabilizer assembly when the one or more internal splines are disengaged from the one or more external splines.
 3. The drilling tool of claim 2, wherein a gripping area of the shaft is accessible when the one or more internal splines are disengaged from the one or more external splines.
 4. The drilling tool of claim 1, wherein a gripping area of the shaft is at least partially covered by the stabilizer assembly when the one or more internal splines are engaged with the one or more external splines.
 5. The drilling tool of claim 1, wherein the shoulder ring is positioned uphole relative to the stabilizer assembly.
 6. The drilling tool of claim 1, further comprising one or more spacers disposed around the housing between the shoulder ring and the stabilizer assembly.
 7. The drilling tool of claim 6, wherein lengths of the one or more spacers are varied to change a position of the stabilizer assembly along the housing.
 8. The drilling tool of claim 6, wherein an inner diameter of the one or more spacers is greater than an outer diameter of the one or more external splines.
 9. The drilling tool of claim 1, wherein an inner diameter of the shoulder ring is greater than an outer diameter of the one or more external splines.
 10. The drilling tool of claim 1, wherein the one or more internal splines are configured to pass through one or more gaps between the one or more external splines to position the shoulder ring uphole relative to the one or more external splines.
 11. The drilling tool of claim 10, wherein the shoulder ring is configured to allow uphole movement of the stabilizer assembly when the shoulder ring is positioned uphole relative to the one or more external splines.
 12. The drilling tool of claim 1, further comprising a blocking ring configured to be engaged with the shoulder ring, wherein the blocking ring comprises: a downhole ring configured to abut a downhole end portion of the shoulder ring, wherein each of the downhole ring and the shoulder ring has an inner diameter greater than an outer diameter of the one or more external splines; and one or more spline arms extending in an axial direction from the downhole ring, wherein an inner diameter of the spline arms is less than an inner diameter of the downhole ring.
 13. The drilling tool of claim 12, wherein each spline arm comprises: an axial arm coupled to the downhole ring and configured to extend axially under the shoulder ring; and a block arm extending laterally from the axial arm, wherein the block arm and the axial arm substantially form an L-shape, and wherein the block arm is configured to cover a gap between external splines, and wherein an uphole end portion of each block arm is configured to align with an uphole end portion of each external spline.
 14. A drilling tool, comprising: a housing having one or more external splines disposed along an outer surface of the housing; a rotatable shaft disposed inside the housing, the shaft having a downhole end portion configured to be coupled to a drill bit; a stabilizer assembly movably coupled to the housing; one or more spacers disposed around the housing between the shoulder ring and the stabilizer assembly; and a shoulder ring disposed around the housing and configured (i) to prevent uphole movement of the stabilizer assembly when one or more internal splines of the shoulder ring are engaged with the one or more external splines and (ii) to allow uphole movement of the stabilizer assembly when the one or more internal splines are disengaged from the one or more external splines.
 15. The drilling tool of claim 14, further comprising a blocking ring configured to be engaged with the shoulder ring, wherein the blocking ring comprises: a downhole ring configured to abut a downhole end portion of the shoulder ring, wherein each of the downhole ring and the shoulder ring has an inner diameter greater than an outer diameter of the one or more external splines; and one or more spline arms extending in an axial direction from the downhole ring, wherein an inner diameter of the spline arms is less than an inner diameter of the downhole ring.
 16. The drilling tool of claim 14, wherein the drilling tool is a turbodrill.
 17. An apparatus for use with a drilling tool, comprising: a shoulder ring having one or more internal splines configured to be engaged with one or more external splines disposed around a housing of a drilling tool; and a blocking ring configured to be engaged with the shoulder ring, wherein the blocking ring comprises: a downhole ring configured to abut a downhole end portion of the shoulder ring, wherein each of the downhole ring and the shoulder ring has an inner diameter greater than an outer diameter of the one or more external splines; and one or more spline arms extending in an axial direction from the downhole ring, wherein an inner diameter of the spline arms is less than an inner diameter of the downhole ring.
 18. The apparatus of claim 17, wherein an inner diameter of the shoulder ring is greater than an outer diameter of the one or more external splines.
 19. The apparatus of claim 17, wherein the one or more internal splines are configured to pass through one or more gaps between the one or more external splines to position the shoulder ring uphole relative to the one or more external splines.
 20. The apparatus of claim 17, wherein each spline arm comprises: an axial arm coupled to the downhole ring and configured to extend axially under the shoulder ring; and a block arm extending laterally from the axial arm, wherein the block arm and the axial arm substantially form an L-shape, and wherein the block arm is configured to cover a gap between external splines, and wherein an uphole end portion of each block arm is configured to align with an uphole end portion of each external spline. 